Antibacterial and antifungal 4,5-dihalopyrrole-2-carbonitriles

ABSTRACT

Phytoresponsive and antimicrobial compositions containing, as the active ingredient, a 4,5-dihalopyrrole-2-carbonitrile and methods of combatting microorganisms and plant growth comprising applying an effective antimicrobial or phytotoxic quantity of the active ingredient to a surface to be disinfected or to undesirable plant growth.

United States Patent [191 Bailey Feb. 4, 1975 ANTIBACTERIAL AND ANTIFUNGAL 4,5-DIIIALOPYRROLE-Z-CARBONITRILES [75] Inventor: Denis M. Bailey, E. Greenbush,

[73} Assignee: Sterling Drug Inc., New York, N.Y. [22] Filed: N0 v. 4, 1971 [2!] Appl. No.: 195,817

UNITED STATES PATENTS 3,663,701 5/1972 Akerstrom v. 424/274 OTHER PUBLICATIONS Chemical Abstracts, Vol. 69 (1968), p. 59090g.

Primary Examiner-Vincent D. Turner Attorney, Agent, or FirmWilliam G. Webb; B. W. Wyatt [57] ABSTRACT Phytoresponsive and antimicrobial compositions containing, as the active ingredient, a 4,5-dihalopyrrole-2- carbonitrile and methods of combatting microorganisms and plant growth comprising applying an effective antimicrobial or phytotoxic quantity of the active ingredient to a surface to be disinfected or to undesirable plant growth.

8 Claims, No Drawings ANTIBACTERIAL AND ANriFu oAL 4.S-DIHALOPYRROLE-Z-CARBONITRILES CHEMICAL COMPOUNDS. COMPOSITIONS AND PROCESSES X- -CN N fr where X is chlorine, bromine or iodine.

In one ofits aspects the instant invention relates to the novel compounds of the above formula I and to methods for the preparation thereof. 7

ln another aspect, the invention relates to compositions for combatting microorganisms containing a 4,5- dihalopyrrole2-carbonitrile of formula I as the active ingredient in effective antimicrobial amount. The invention also relates to a method of combatting microorganisms comprising treating a surface to be disinfected with a composition containing an effective antimicrobial amount of the said active ingredient.

In another of its aspects, the invention relates to aquatic and terrestrial herbicidal compositions containing an effective herbicidal amount of a 4,5- dihalopyrrole-Z-carbonitrile of formula I as the active ingredient.

Another aspect of the invention relates'to a method of combatting undesirable terrestrial or aquatic plant growth which comprises treating an area to be cleared of such undesirable terrestrial plant growth, or a body of water to be cleared of such undesirable aquatic plant growth, with a composition containing a herbicidally effective amount of a 4,5-dihalopyrrole-Z-caronitrile of formula I as the active ingredient. When used as terrestrial herbicides, the 4,5-dihalopyrrole-2-carbonitrile containing composition is either sprayed, dusted, or otherwise scattered as described hereinafter over an entire area to be cleared of undesirable vegetation, or

alternatively individual plants can be similarly treated,

When used as aquatic herbicides to destroy plant growth growing in a particular body of water, either the 4,5-dihalopyrrole-2-carbonitrile itself, or a composition containing it, is dissolved directly in the body of water in an amount, to be described hereinafter, sufficient to provide a herbicidally effective concentration of the active ingredient in the body of water being treated.

The compounds of formula I are generally prepared by direct halogenation of pyrrole-Z-carbonitrile. In the case of the compounds where X is chlorine or bromine, the halogenation is advantageously carried out with the elemental halogen in glacial acetic acid at a temperature from C. to around 50C.

The compounds where X is iodine, on the other hand, are advantageously prepared by reaction of pyrrole-Z-carbonitrile with a solution of iodine monochloride and sodium or potassium chloride in aqueous acetic acid at a temperature from 20C. to around 100C.

sponding nitrile by reaction of the oxime with acetic anhydride at a temperature from 40C. to around l00C. This latter method is illustrated by the following reaction sequence:

x1" al ltry - H NOH CHO . i ii=non xi i-cn where X has the meanings given above. The 4,5-

dihalopyrrole-Q-carboxaldehydes in turn are prepared by direct halogenation of pyrrole-Z -carboxaldehyde by methods similar to those described above for the halogenation of pyrrole-Z-carbonitrile to the corresponding 4,5-dihalopyrrole-2-carbonitrile.

The compounds of the invention are formulated for.

use as antimicrobial agents by preparing a dilute solution in an organic medium in which the compounds are soluble, for example ethyl alcohol, acetone, dimethylsulfoxide, and the like, and are applied to a surface to be disinfected, or which is susceptible to contamination, by conventional means such as spraying, swabbing, immersion, and the like. Alternatively, the compounds can be formulated as ointments or creams by incorporating them in conventional ointment or cream bases, as alkylpolyether alcohols, cetyl alcohol, stearyl alcohol and the like, or as jellies by incorporating them in conventional jelly bases such as glycerin and tragacanth. They can also be formulated for use as aerosol sprays or foams.

The undesired microoraganisms against which the instant compounds are effective may be pathogenic or not but whose presence is unwanted and thus include bacteria, fungi, protozoa, algae, and various other forms of microorganisms well-known tomicrobiology.

The compounds of the invention are formulated for use as either pre-emergent or post-emergent terrestrial herbicides or as aquatic herbicides by mixing the pure active ingredient with conventional pest control and herbicidal adjuvants, modifiers, diluents or conditioning agents so that they may be formulated as solutions, emulsions, dispersions, dusts or wettable powders.

Liquid formulations of the active compounds according' to the present invention for direct herbicidal spraying may be made, for example, with'water or water ents. The wetting, emulsifying or dispersing agents may oils; quaternary salts of high molecular weight acids;

rosin soaps such as salts'of abietic acid, sulfuric acid salts of high molecular weight organic compounds; algin soaps; and simple and polymeric compositions having both hydrophobic and hydrophilic functions.

Herbicidaldusts may be prepared by mixing or grinding the active substance with a solid carrier material such as talc, diatomaceous earth, kaolin, bentonite, calcium carbonate, boric acid, calcium phosphate, wood, flour, cork, dust, carbon, and the like. Scatterable granules may be obtained, for example, by using ammonium sulfate as carrier material. Alternatively, carrier materials may be impregnated with solutions of the active substances in liquid solvents. Powder preparations or pastes which can be suspended in water and used as sprays may be obtained by adding wetting agents and protective colloids. Different forms of application may be better adapted to the various purposes for which the active substances are to be used by the addition of substances which improve dispersion, adhesion, resistance to rain, and penetrative power such as fatty acids, resins, wetting agents, emulsifying agents, glue and the like. Similarly, the biological spectrum may be broadened by the addition of other substances having bactericidal, fungicidal and plant growth regulating'properties and also by combination with fertilizers.

Optimum preand post-emergent herbicidal action is obtained using the compounds of the invention at ap-' plication rates from 1.0 to 8.0 pounds per acre, while optimum aquatic herbicidal activity is obtained using a solution concentration of the active ingredient of from about 1.0 to 40 parts per million. v

The following examples illustrate the best mode of making and using the instant invention.

EXAMPLE 1 4,5-Dichloropyrrole 2-carbonitri1e To a solution of 33.5 g. (0.47 mole) of hydroxylamine hydrochloride and 67 g. (0.48 mo1e) of sodium acetate trihydrate in 130 ml. of water was added 40 g. (0.42 mole) of pyrrole-2-carboxaldehyde. The mixture was shaken vigorously for 5 minutes, cooled in a refrigerator for several days, filtered, and dried giving 45.5 g. of pyrrole-2-carboxaldoxime, m.p. l65 l68C.

The latter was treated with 150 ml. of acetic anhydride, and after the initial exothermic reaction had subsided, the mixture was stirred and heated slowly to reflux for twenty minutes. The mixture was then cooled and poured into 1500 ml. of water, the mixture extracted with diethyl ether, and the combined extracts charcoaled, concentrated and distilled in vacuo, giving a total of 19.0 g. of pyrrole-2-carb'onitrile, b.p.

133l45C./25 mm.

The latter g., 0.11 mole), dissolved in 40 m1. of glacial acetic acid, was treated slowly with stirring with a solution of 15.6 g. (0.22 mole) of chlorine dissolved in 300 ml. of glacial acetic acid. The mixture was stirred for whom and a half. concentrated to a small volume in vacuo, the residue dissolved in diethyl ether,

and the organic solution washed with aqueous sodium bicarbonate until the aqueous layer was slightly basic. The organic solution was then dried with anhydrous sodium sulfate, concentrated to dryness and the residue recrystallized from a diethyl ether/hexane mixture giving 9.0 g. of 4,5-dichloropyrrole-Z-carbonitrile, m.p. 144-l 46C.

EXAMPLE 2 4,5-Dibromopyrrole-Z-carbonitrile A solution of g. (0.099 mole) of 4,5.- dibromopyrrole-2-carboxaldehyde [prepared according to the method of Anderson et al., Can. J. Chem. 43(2), 409-414 1965)] and 10.5 g. (0.15 mole) of hydroxylamine hydrochloride in 100 ml. of ethanol was heated on a steam bath with stirring for 5 minutes until all solid material had dissolved. The resulting solution was treated with a solution of 10.5 g. of potassium carbonate in 20 ml. of water, heating and stirring was conbath for ten minutes. Concentration of the mixture to,

dryness in vacuo gave a black residue which was dissolved in diethyl ether. The ether solution was dried over sodium sulfate, charcoaled, concentrated to a small volume, and the solid which separated was re-- crystallized several times from diethyl ether/hexane to give 12.3 g. of 4,5-dibromopyrrole-Z-Carbonitrile, m.p. l72-174C. (uncorr.)

EXAMPLE 3 4,5-Diiodopyrrole-2-carbonitrile I A solution of 9.2 g. (0.10 mole) of pyrrole-Z- carbonitrile in ml. of glacial acetic acid was stirred on a steam bath while 45 ml. of a 4.68N aqueous solution of iodine monochloride/sodium chloride was added slowly over a period of about 15 minutes. The mixture was stirred at 50C. for about 4 hours, and the precipitate which'had separated was collected and dissolved in diethyl ether. The organic solution was washed first with 200 ml. of water, then with 400 ml. of saturated aqueous sodium bicarbonate, dried over anhydrous magnesium sulfate, and concentrated to dryness to give a solid residue. Recrystallization of the latter from ethyl acetate/hexane afforded 16.5 g. of 4,- 5-diiodopyrrole-2-carbonitrile, mp 21 l2l3C. (uncorr.) v I Anti-bacterial and anti-fungal activities for the compounds were'established using standard serial dilution techniques as described by Goss and Cimijotti, Applied Microbiology, 16 1414-1416 (1968). The minimum (bactericidal and fungicidal) inhibitory concentrations (MIC) of the compounds thus tested as solutions against a variety of bacteria including Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia (o/i, and Proteus vulgaris and against such fungi as Triclwphymn mentagrophyles, Aspergillus niger, and Candida albicans were found to be in the range from 8.0 to mcg./ml.

Pre-emergence herbicidal activity for the compounds of the invention was establised in an initial screening procedure described as follows: Test crop seeds of five different species of plant growth (lima beans, Dent corn. lettuce. mustard and crabgrass, which were selected as representative of the major classes of monoand dicotyledonous plants) were planted in 8 X 6 X 3 inch flat-bed trays containing 2 to 3 inches of sandy Post-emergence herbicidal activity for the compounds of the invention was established in an initial screening procedure described as follows: Test crop seeds of the same plant species used in the preemergence herbicidal tests were planted in 8 X 6 X 3 inch shallow flat-bed trays containing two to three inches of a loam soil. The growth trays were maintained loam 5011' l l f flh after plandtmg' an aquzous 5 in a greenhouse and watered regularly for approxidcemrie 50 O t 6 test compoun was Spraye on mately 2 weeks. When the first trifoliate leaves of the the SOll at a rate of 8 pounds of test agent per acre. The

. bean plants began to unfold. the test plants were replants were maintained in a greenhouse and watered moved from the reenhouge and g m d with, I regularly for 2 weeks. after which time the phytotoxio I v ye aqueity of the test compound was recorded by examining m gus acetonefsolution of the test compound at a rate of individual plant species for percent kill and assigning a pound? O the ,test compound per acre The plumb vigor rating to the surviving members of the species acwere mammmed, the green'hnuse and rcgu' cording to the following scale. larly for an additional 2 weeks. after which time the 5 plants normal phytotoxicity of the test compound was recorded by 4 li ht injury noting the percent kill and assigning a vigor rating to 3 moderate i j Plants expected to recover surviving plants as described above. As in other tests 2 moderate to Severe i j plants not expected described previously, untreated control plants were to recover maintained in every test. The results thus obtained are l severe injury; plants will not recover. given in TABLE C below. Untreated control plants were maintained in every test carried out. The results thus obtained using the Compounds of Examples 1. 2 and 3 above are given in TABLE C TABLE A below.

TABLE A 78 TEST Example 1 Example 2 Example 3 I PLANT TEST Example I p 2 Exumplc 3 SPECIES Vigor /(Kill Vigor /1 Kill Vigor /1 Kill PLANT Lima Bean 100 a 7 I00 2 a 60 SPEClES Vigor 71Kill Vigor /Kill Vigor 7(Kill Dcm Com mu 3 a 4 O 1 V Lettuce 100 a l()() 100 23 8 g 30 Mustard 100 a 2 70 m0 Lcuucc I00 [00 5 0 Crahgrass I00 1 l0) lilU Mustard 3 (J 2 9O 5 U Crabgrass loo 2 9O 5 (l a Desiccation a Stunted h Desiceulion Using the same test plant species and the same proce- UsingtheameteSFP1fmt5peCieS and the S F dure usedin the initial pre-emergence herbicidal dure. m the l postemergencei herb'cdal screening test described above. the compound of Ex- Screenmg test lescrlbed above, the Compound of ample 1 (4,5-dichloropyrrole-Lcarbonitrile) was ree- Ple l (4, py W218 valuated for pre-emergence herbicidal activity ata rate Valuated for Post-emergence hefblcidal activity at 11 of 8 pounds per acre and submultiples thereof, i.e., 4 rate of8 pounds per acre and submultiples thereof. i.e., pounds/acre, 2 pounds/acre, and l pound/acre. The re- 4 pounds/acre, 2 pounds/acre, and 1 pound/acre. The sults thus obtained are given in TABLE B below. results thus obtained are given in TABLE D below.

TABLE D TEST 1.0 lb/A 2.0 lb/A 4.0 lb/A 8.0 lb/A PLANT SPECIES Vigor '71Kill Vigor 7(Kill Vigor /cKill Vigor /(Kill Lima Bean 3 6O 2 70 2 70 100 Dent Corn 3 0 3 30 2 70 2 7O 7 Lettuce I00 (25 I00 100 Mustard 3 20 3 70 2 m0 Crabgrass 7 90 [00 I00 I00 TABLE B TEST L0 lb/A 2.0 lb/A 4.0 lb/A 8.0 lb/A PLANT SPEClES Vigor 7zKill Vigor Kill Vigor /zKill Vigor 7zKill Lima Bean 3 0 4 0 I00 2 70 Dent Corn 4 0 5 0 4 O 3 0 Lettuce 4 0 100 100 100 Mustard 4 0 4 0 2 90 2 30 Crabgrass 3 O l I00 For the purpose of determining the aquatic herbicidal activity of the compounds of the invention. a nutrient solution constituted as follows was prepared:

7 Component Cone. (g/l) KNO 0202 CatNQ-Q AH O 0.709 KH PO 0. l 36 MgSO, 0. [20 Ci-lCIg-ZH O 0.44l KCl 0. I49 MgCl .6H O 0.20.1 Thiamine 0.0001 Pyridoxinc 0.0008 Nicotinamide 0.0008 H 50 (HJUUI MnC|,.4H,0 0,0001 ZnSO,.7H O 0.0003 CuSO,.5H O 0.000l Na MoO,.H O 0.000] Iron Versenol (N-carboxymethyll- N-( 2'hydroxycthyl J-N,N '-ethylenediglycine iron salt) 0.005

A sufficient quantity of the test compound to provide a concentration of 5 ppm of active ingredient was dissolved in about 800 ml. of the nutrient solution. To this solution was added 25 to 30 duckweed plants (Lemma minor L.) and three snails (He/isoma Irivolvis). The solutions with the plants and snails were maintained throughout the test at 25C. under artificial light. Twenty-four hours later, the solutions were examined for snail mortality, and nine days later, the percent reduction of growth of the plants, relative to an untreated control, was recorded. The test solutions were also examined for presence of algae, plant growth aberration, and chlorosis. The results thus obtained are given in TABLE E below.

TABLE E Example "/rKill Snails Killed l l no 2 l00 a 3 100 a a Algicidal ous solution. The container holding the toxicant solution. test plants and a few snails was placed under artificial light in a growth chamber, maintained at about 25C., and after periods of l, 2, 3, and 4 weeks, during which the solution volume in the testcontainers was maintained, test plants were examined for kill or reduction of growth compared to plants grown in an aqueous, untreated environment. The plants were rated on a scale of l to 5 as indicated above, and in addition, the growth of algae, plant aberration, and snail kill were recorded. The results thus obtained are given in TABLE F below, where the initials P., M E., C., A D., and W., at the head of the various columns represent the respective aquatic plants, purslane, milfoil, elodea, crowfoot. arrowhead. duckweed, and wolffia.

TABLE F Concen. Week of Growth Reduction Snails (ppm) test P M. E. C. A. D W. Dead 40 one 2 2 2 2 2 2 2 yes two 2 2 2 2 2 2 1 yes three I l l l l 3 2 yes four 1 I 2 l l 3 1 yes 20 one 2 2 2 2. 2 3 3 no two 2 2 2 2 2 3 3 yes three I l l l l 4 3 yes four l l 2 l l 5 3 yes 10 one 2 2 2 2 3 3 3 no two 1 l 2 2 2 3 2 yes three 2 2 2 2 2 3 2 yes four l l 2 l 2 5 3 yes 5 one 3 4 4 2 4 4 3 no two 2 3 2 l 2 4 4 yes three 2 2 2 2 3 3 4 yes four l l '2 l 3 4 l yes I one 2 2 3 -2 .3 l 1 yes two l l l l l 2 2 yes three l l l l 2 2 yes four I l l l 2 2 l \es 0.5 one 5 5 5 5 v 5 5 5 no two 5- 5 5 5 5 5 5 no three 5 5 5 5 5 5 5 no four 5 5 5 5 5 5 5 no Control all 5 5 5 5 5 5 5 no I claim:

1. An antibacterial or antifungal composition consisting essentially of an effective antibacterial or antifungal amount ofa 4,5-dihalopyrrole-2-carbonitrile having the formula:

where X is chlorine, bromine or iodine as the active ingredient and a conventional diluent especially adapting the composition for application to areas to be disinfe'cted of deleterious bacteria or fungi.

2. The composition according to claim I wherein the 4,5-dihalopyrrole-Z-carbonitrile is 4,5-dichloropyrrole- 2-c'arbonitrile. i

3. The composition according to claim 1 wherein the 4,5-dihalopyrrole-Z-carbonitrileis 4,5-dibromopyrrole- 2-carbonitrile. V

4. The composition according to claim 1 wherein the 4,5-dihalopyrrole-Z-carbonitrile is 4,5-diiodopyrrole-2- carbonitrile.

5. A method of combatting bacteria or fungi comprising applying to an area to be disinfected an effective antibacterial or antifungal amount of a dihalopyrrole-2-carbonitrileaccording to Claim 1.

6. The method according to claim 5 wherein the 4,5-

dihalopyrrole-Z-carbonitrile is 4,5-dichloropyrrole2- carbonitrile.

7. The method according to claim 5 wherein the 4,5- dihalopyrrole-Z-carbonitrile is 4,5-dibromopyrrole-2- carbonitrile.

8. The method according to claim 5 wherein the 4,5- dihalopyrrole-Z -carbonitrile is 4,5-diiodopyrrol-2- carbonitrile. 

1. AN ANTIBACTERIAL OR ANTIFUNGAL COMPOSITION CONSISTING ESSENTIALLY OF AN EFFECTIVE ANTIBACTERIAL OR ANTIFUNGAL AMOUNT OF A 4,5-DIHALOPYRROLE-2-CARBONITRILE HAVING THE FORMULA:
 2. The composition according to claim 1 wherein the 4,5-dihalopyrrole-2-carbonitrile is 4,5-dichloropyrrole-2-carbonitrile.
 3. The composition according to claim 1 wherein the 4,5-dihalopyrrole-2-carbonitrile is 4,5-dibromopyrrole-2-carbonitrile.
 4. The composition according to claim 1 wherein the 4,5-dihalopyrrole-2-carbonitrile is 4,5-diiodopyrrole-2-carbonitrile.
 5. A method of combatting bacteria or fungi comprising applying to an area to be disinfected an effective antibacterial or antifungal amount of a 4,5-dihalopyrrole-2-carbonitrile according to Claim
 1. 6. The method according to claim 5 wherein the 4,5-dihalopyrrole-2-carbonitrile is 4,5-dichloropyrrole-2-carbonitrile.
 7. The method according to claim 5 wherein the 4,5-dihalopyrrole-2-carbonitrile is 4,5-dibromopyrrole-2-carbonitrile.
 8. The method according to claim 5 wherein the 4,5-dihalopyrrole-2-carbonitrile is 4,5-diiodopyrrole-2-carbonitrile. 